Let us say I began by helping cover their one domain on the server known as "world wide web.oldsite.com". I Quickly made the decision to join up another domain,"world wide web.newsite.com" and set the brand new domain's files in to the directory, "world wide web.oldsite.com/newsite/". How do you permit the user to go to "world wide web.newsite.com" and access the web pages from the new site.

You are searching for host header redirection. This really is set up in a different way for every web server, however the concept is identical. Once the HTTP request is available in, the net server inspections the host title, and redirects towards the correct application accordingly.

Host Headers in IIS7: http://technet.microsoft.com/en-us/library/cc753195%28WS.10%29.aspx

Virtual Hosts in Apache: http://httpd.apache.org/paperwork/2./vhosts/title-based.html